<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
  <div id="root">
    <div>{{name}}</div>
    <div>{{age}}</div>
    <div>hello2</div>
    <ul>
      <li>1</li>
      <li>2</li>
      <li>3</li>
    </ul>
  </div>
</body>
  <script>
    function func(){
      console.log('原始功能')
    }

    let _temFn = func;

    func = function(){
      _temFn();
      console.log('扩展功能')
    }
    func();
  </script>
</html>